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FeatureTableQueryFeaturesAsync Method (QueryParameters)

Asynchronously performs query against the table.

Namespace:  Esri.ArcGISRuntime.Data
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.11.0
Syntax
public Task<FeatureQueryResult> QueryFeaturesAsync(
	QueryParameters parameters
)

Parameters

parameters
Type: Esri.ArcGISRuntime.DataQueryParameters
The QueryParameters used to filter feature results.

Return Value

Type: TaskFeatureQueryResult
A task that represents the asynchronous query features operation. The value of the task result contains a FeatureQueryResult object.
Examples

UWP

Example Name: DeleteFeatures

Delete features from an online feature service.

Code example screen shot.

C#
// Copyright 2019 Esri.
// 
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an 
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific 
// language governing permissions and limitations under the License.

using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.UI.Controls;
using System;
using System.Linq;
using Windows.UI.Popups;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace ArcGISRuntime.UWP.Samples.DeleteFeatures
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Delete features (feature service)",
        category: "Data",
        description: "Delete features from an online feature service.",
        instructions: "To delete a feature, tap it, then click 'Delete incident'.",
        tags: new[] { "Service", "deletion", "feature", "online", "table" })]
    public partial class DeleteFeatures
    {
        // Path to the feature service.
        private const string FeatureServiceUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/DamageAssessment/FeatureServer/0";

        // Hold a reference to the feature layer.
        private FeatureLayer _damageLayer;

        public DeleteFeatures()
        {
            InitializeComponent();
            Initialize();
        }

        private void Initialize()
        {
            // Create the map with streets basemap.
            MyMapView.Map = new Map(BasemapStyle.ArcGISStreets);

            // Create the feature table, referring to the Damage Assessment feature service.
            ServiceFeatureTable damageTable = new ServiceFeatureTable(new Uri(FeatureServiceUrl));

            // Create a feature layer to visualize the features in the table.
            _damageLayer = new FeatureLayer(damageTable);

            // Add the layer to the map.
            MyMapView.Map.OperationalLayers.Add(_damageLayer);

            // Listen for user taps on the map - on tap, a callout will be shown.
            MyMapView.GeoViewTapped += MapView_Tapped;

            // Zoom to the United States.
            MyMapView.SetViewpointCenterAsync(new MapPoint(-10800000, 4500000, SpatialReferences.WebMercator), 3e7);
        }

        private async void MapView_Tapped(object sender, GeoViewInputEventArgs e)
        {
            // Clear any existing selection.
            _damageLayer.ClearSelection();

            // Dismiss any existing callouts.
            MyMapView.DismissCallout();

            try
            {
                // Perform an identify to determine if a user tapped on a feature.
                IdentifyLayerResult identifyResult = await MyMapView.IdentifyLayerAsync(_damageLayer, e.Position, 2, false);

                // Do nothing if there are no results.
                if (!identifyResult.GeoElements.Any())
                {
                    return;
                }

                // Otherwise, get the ID of the first result.
                long featureId = (long) identifyResult.GeoElements.First().Attributes["objectid"];

                // Get the feature by constructing a query and running it.
                QueryParameters qp = new QueryParameters();
                qp.ObjectIds.Add(featureId);
                FeatureQueryResult queryResult = await _damageLayer.FeatureTable.QueryFeaturesAsync(qp);
                Feature tappedFeature = queryResult.First();

                // Select the feature.
                _damageLayer.SelectFeature(tappedFeature);

                // Show the callout.
                ShowDeletionCallout(tappedFeature);
            }
            catch (Exception ex)
            {
                await new MessageDialog(ex.ToString()).ShowAsync();
            }
        }

        private void ShowDeletionCallout(Feature tappedFeature)
        {
            // Create a button for deleting the feature.
            Button deleteButton = new Button();
            deleteButton.Content = "Delete incident";
            deleteButton.Padding = new Thickness(5);
            deleteButton.Tag = tappedFeature;

            // Handle button clicks.
            deleteButton.Click += DeleteButton_Click;

            // Show the callout.
            MyMapView.ShowCalloutAt((MapPoint) tappedFeature.Geometry, deleteButton);
        }

        private async void DeleteButton_Click(object sender, RoutedEventArgs e)
        {
            // Dismiss the callout.
            MyMapView.DismissCallout();

            try
            {
                // Get the feature to delete from the layer.
                Button deleteButton = (Button) sender;
                Feature featureToDelete = (Feature) deleteButton.Tag;

                // Delete the feature.
                await _damageLayer.FeatureTable.DeleteFeatureAsync(featureToDelete);

                // Sync the change with the service.
                ServiceFeatureTable serviceTable = (ServiceFeatureTable) _damageLayer.FeatureTable;
                await serviceTable.ApplyEditsAsync();

                // Show a message confirming the deletion.
                await new MessageDialog($"Deleted feature with ID {featureToDelete.Attributes["objectid"]}", "Success!").ShowAsync();
            }
            catch (Exception ex)
            {
                await new MessageDialog(ex.ToString(), "Couldn't delete feature.").ShowAsync();
            }
        }
    }
}
XAML
<UserControl 
    x:Class="ArcGISRuntime.UWP.Samples.DeleteFeatures.DeleteFeatures"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:esriUI="using:Esri.ArcGISRuntime.UI.Controls">
    <Grid>
        <esriUI:MapView x:Name="MyMapView" />
        <Border Style="{StaticResource BorderStyle}">
            <TextBlock Text="Tap a feature to select it for deletion."
                       TextAlignment="Center" FontWeight="SemiBold" />
        </Border>
    </Grid>
</UserControl>
Examples

Xamarin Forms UWP

Example Name: DeleteFeatures

Delete features from an online feature service.

Code example screen shot.

C#
// Copyright 2019 Esri.
// 
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an 
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific 
// language governing permissions and limitations under the License.

using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using System;
using System.Linq;
using Xamarin.Forms;

namespace ArcGISRuntimeXamarin.Samples.DeleteFeatures
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Delete features (feature service)",
        category: "Data",
        description: "Delete features from an online feature service.",
        instructions: "To delete a feature, tap it, then tap 'Delete incident'.",
        tags: new[] { "Service", "deletion", "feature", "online", "table" })]
    public partial class DeleteFeatures : ContentPage
    {
        // Path to the feature service.
        private const string FeatureServiceUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/DamageAssessment/FeatureServer/0";

        // Hold a reference to the feature layer.
        private FeatureLayer _damageLayer;

        // Hold a reference to the most recently tapped feature.
        private Feature _tappedFeature;

        public DeleteFeatures()
        {
            InitializeComponent();
            Initialize();
        }

        private void Initialize()
        {
            // Create the map with streets basemap.
            MyMapView.Map = new Map(BasemapStyle.ArcGISStreets);

            // Create the feature table, referring to the Damage Assessment feature service.
            ServiceFeatureTable damageTable = new ServiceFeatureTable(new Uri(FeatureServiceUrl));

            // Create a feature layer to visualize the features in the table.
            _damageLayer = new FeatureLayer(damageTable);

            // Add the layer to the map.
            MyMapView.Map.OperationalLayers.Add(_damageLayer);

            // Listen for user taps on the map - on tap, a callout will be shown.
            MyMapView.GeoViewTapped += MapView_Tapped;

            // Zoom to the United States.
            MyMapView.SetViewpointCenterAsync(new MapPoint(-10800000, 4500000, SpatialReferences.WebMercator), 3e7);
        }

        private async void MapView_Tapped(object sender, Esri.ArcGISRuntime.Xamarin.Forms.GeoViewInputEventArgs e)
        {
            // Clear any existing selection.
            _damageLayer.ClearSelection();

            // Reconfigure the button.
            DeleteButton.IsEnabled = false;
            DeleteButton.Text = "Delete feature";

            try
            {
                // Perform an identify to determine if a user tapped on a feature.
                IdentifyLayerResult identifyResult = await MyMapView.IdentifyLayerAsync(_damageLayer, e.Position, 5, false);

                // Do nothing if there are no results.
                if (!identifyResult.GeoElements.Any())
                {
                    return;
                }

                // Otherwise, get the ID of the first result.
                long featureId = (long) identifyResult.GeoElements.First().Attributes["objectid"];

                // Get the feature by constructing a query and running it.
                QueryParameters qp = new QueryParameters();
                qp.ObjectIds.Add(featureId);
                FeatureQueryResult queryResult = await _damageLayer.FeatureTable.QueryFeaturesAsync(qp);
                _tappedFeature = queryResult.First();

                // Select the feature.
                _damageLayer.SelectFeature(_tappedFeature);

                // Update the button to allow deleting the feature.
                ConfigureDeletionButton(_tappedFeature);
            }
            catch (Exception ex)
            {
                await Application.Current.MainPage.DisplayAlert("Error", ex.ToString(), "OK");
            }
        }

        private void ConfigureDeletionButton(Feature tappedFeature)
        {
            // Create a button for deleting the feature.
            DeleteButton.Text = $"Delete incident {tappedFeature.Attributes["objectid"]}";
            DeleteButton.IsEnabled = true;
        }

        private async void DeleteButton_Click(object sender, EventArgs e)
        {

            // Reconfigure the button.
            DeleteButton.IsEnabled = false;
            DeleteButton.Text = "Delete feature";

            // Guard against null.
            if (_tappedFeature == null)
            {
                return;
            }

            try
            {
                // Delete the feature.
                await _damageLayer.FeatureTable.DeleteFeatureAsync(_tappedFeature);

                // Sync the change with the service.
                ServiceFeatureTable serviceTable = (ServiceFeatureTable) _damageLayer.FeatureTable;
                await serviceTable.ApplyEditsAsync();

                // Show a message confirming the deletion.
                await Application.Current.MainPage.DisplayAlert("Success!", $"Deleted feature with ID {_tappedFeature.Attributes["objectid"]}", "OK");
            }
            catch (Exception ex)
            {
                await Application.Current.MainPage.DisplayAlert("Error", ex.ToString(), "OK");
            }
        }
    }
}
XAML
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"             
             xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Xamarin.Forms;assembly=Esri.ArcGISRuntime.Xamarin.Forms"
             xmlns:resources="clr-namespace:Forms.Resources;assembly=ArcGISRuntime"
             x:Class="ArcGISRuntimeXamarin.Samples.DeleteFeatures.DeleteFeatures">
    <RelativeLayout>
        <esriUI:MapView x:Name="MyMapView" Style="{StaticResource MapWithFormStyle}"
                        BindingContext="{x:Reference Name=ResponsiveFormContainer}" />
        <resources:ResponsiveFormContainer x:Name="ResponsiveFormContainer">
            <StackLayout>
                <Label Text="Tap to select a feature to delete."
                       HorizontalTextAlignment="Center"/>
                <Button x:Name="DeleteButton" 
                        Text="Delete feature"
                        Clicked="DeleteButton_Click"
                        IsEnabled="False"/>
            </StackLayout>
        </resources:ResponsiveFormContainer>
    </RelativeLayout>
</ContentPage>
See Also
Additional Examples
Hyperlink to ExampleDescription
ClosestFacilityStaticFind routes from several locations to the respective closest facility.
DeleteFeaturesDelete features from an online feature service.
FeatureCollectionLayerFromQueryCreate a feature collection layer to show a query result from a service feature table.
FeatureLayerQueryFind features in a feature table which match an SQL query.
MapImageSublayerQueryFind features in a sublayer based on attributes and location.